The non-custodial Spark Savings USDT vault, built on the ERC-4626 standard, saw its total value locked grow to $600 million over a two-week period. The vault operates on Ethereum, Arbitrum, and X Layer, utilizing the Spark Liquidity Layer to deploy assets into lending protocols like SparkLend.
The growth follows an integration with the OKX app in September 2026, which allows users to deposit USDT directly without managing cross-chain bridges or external wallets. This move simplified access for exchange customers, contributing to the recent surge in deposits.
While deposits increased, the annual percentage yield has compressed. Current rates are reported between 3% and 3.75%, down from previous peaks that exceeded 4%. This decline is attributed to the influx of capital outpacing borrowing demand within the lending pools.
The vault maintains 1:1 backing by USDS and issues spUSDT tokens to represent user shares. Spark also manages similar products for other dollar-pegged tokens, including spUSDC and sUSDS. The platform previously demonstrated its liquidity buffers during market stress in April 2026.
